243 lines
8.2 KiB
C
243 lines
8.2 KiB
C
/* vim: set sw=8 ts=8 sts=8 noet: */
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#ifndef CAPN_H
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#define CAPN_H
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#include <stdint.h>
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typedef struct capn_segment *(*capn_create_t)(void* /*user*/, int /*sz*/);
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typedef struct capn_segment *(*capn_lookup_t)(void* /*user*/, uint32_t /*id*/);
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/* struct capn is a common structure shared between segments in the same
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* session/context so that far pointers between the segments will be created.
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* lookup is used to lookup segments by id when derefencing a far pointer
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* create is used to create or lookup an alternate segment that has at least
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* sz available (ie returned seg->len + sz <= seg->cap)
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* create and lookup can be NULL if you don't need multiple segments
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*/
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struct capn {
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struct capn_segment *(*lookup)(void* /*user*/, uint32_t /*id */);
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struct capn_segment *(*create)(void* /*user*/, int /*sz*/);
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void *user;
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};
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/* struct capn_segment contains the information about a single segment.
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* capn should point to a struct capn that is shared between segments in the
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* same session
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* id specifies the segment id, used for far pointers
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* data specifies the segment data. This should not move once.
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* len specifies the current segment length. This should be 0 for a blank
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* segment.
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* cap specifies the segment capacity.
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* When creating new structures len will be incremented until it reaces cap,
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* at which point a new segment will be requested via capn->create.
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*
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* data, len, and cap must all by 8 byte aligned
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*/
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struct capn_segment {
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struct capn *capn;
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uint32_t id;
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char *data;
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int len, cap;
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};
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enum CAPN_TYPE {
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CAPN_NULL = 0,
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CAPN_STRUCT = 1,
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CAPN_LIST = 2,
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CAPN_PTR_LIST = 3,
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CAPN_BIT_LIST = 4,
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};
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struct capn_ptr {
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enum CAPN_TYPE type;
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int size;
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char *data;
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struct capn_segment *seg;
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uint32_t datasz;
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uint32_t ptrsz;
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};
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struct capn_string {
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struct capn_ptr p;
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const char *str;
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int size;
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};
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struct capn_data{struct capn_ptr p;};
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struct capn_list_8{struct capn_ptr p;};
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struct capn_list_16{struct capn_ptr p;};
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struct capn_list_32{struct capn_ptr p;};
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struct capn_list_64{struct capn_ptr p;};
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/* capn_read|write_ptr functions read/write ptrs to list/structs
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* off is the list index or pointer index in a struct
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* capn_write_ptr will copy the data, create far pointers, etc if the target
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* is in a different segment/context.
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* Both of these will use/return inner pointers for composite lists.
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*/
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struct capn_ptr capn_read_ptr(const struct capn_ptr *p, int off);
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int capn_write_ptr(struct capn_ptr *p, int off, struct capn_ptr *tgt);
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/* capn_to_string returns a pointer to a string
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* Use this instead of accessing the data directly as these checks that the
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* string is null terminated, the list type, etc.
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* psz is filled out with the string length if non NULL
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*/
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char *capn_to_string(const struct capn_string *p, int *psz);
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/* capn_copy copies data from 'from' to 'to'
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* returns 0 on success, non-zero on error (type mismatch, allocation error,
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* etc).
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*/
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int capn_copy(struct capn_ptr *to, const struct capn_ptr *from);
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/* capn_read_* functions read data from a list
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* The length of the list is given by p->size
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* off specifies how far into the list to start
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* sz indicates the number of elements to read
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* The function returns the number of elements read or -1 on an error.
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* off must be byte aligned for capn_read_1
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*/
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int capn_read_1(const struct capn_list_1 *p, int off, uint8_t *data, int sz);
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int capn_read_8(const struct capn_list_8 *p, int off, uint8_t *data, int sz);
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int capn_read_16(const struct capn_list_16 *p, int off, uint16_t *data, int sz);
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int capn_read_32(const struct capn_list_32 *p, int off, uint32_t *data, int sz);
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int capn_read_64(const struct capn_list_64 *p, int off, uint64_t *data, int sz);
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/* capn_write_* function write data to a list
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* off specifies how far into the list to start
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* sz indicates the number of elements to write
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* The function returns the number of elemnts written or -1 on an error.
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* off must be byte aligned for capn_read_1
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*/
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int capn_write_1(struct capn_list_1 *p, int off, const uint8_t *data, int sz);
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int capn_write_8(struct capn_list_8 *p, int off, const uint8_t *data, int sz);
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int capn_write_16(struct capn_list_16 *p, int off, const uint16_t *data, int sz);
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int capn_write_32(struct capn_list_32 *p, int off, const uint32_t *data, int sz);
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int capn_write_64(struct capn_list_64 *p, int off, const uint64_t *data, int sz);
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/* capn_new_* functions create a new object
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* datasz is in bytes, ptrs is # of pointers, sz is # of elements in the list
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* If capn_new_string sz < 0, strlen is used to compute the string length
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* On an error a CAPN_NULL pointer is returned
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*/
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struct capn_ptr capn_new_struct(struct capn_segment *seg, int datasz, int ptrs);
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struct capn_ptr capn_new_list(struct capn_segment *seg, int sz, int datasz, int ptrs);
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struct capn_ptr capn_new_bit_list(struct capn_segment *seg, int sz);
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struct capn_ptr capn_new_ptr_list(struct capn_segment *seg, int sz);
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struct capn_ptr capn_new_string(struct capn_segment *seg, const char *str, int sz);
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/* capn_get|set_* functions get/set struct values
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* off is the offset into the structure in bytes
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* Rarely should these be called directly, instead use the generated code.
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* Data must be xored with the default value
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* These are static in order to be inlined.
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*/
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static uint8_t capn_get_8(const struct capn_ptr *p, int off);
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static uint16_t capn_get_16(const struct capn_ptr *p, int off);
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static uint32_t capn_get_32(const struct capn_ptr *p, int off);
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static uint64_t capn_get_64(const struct capn_ptr *p, int off);
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static int capn_set_8(struct capn_ptr *p, int off, uint8_t val);
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static int capn_set_16(struct capn_ptr *p, int off, uint16_t val);
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static int capn_set_32(struct capn_ptr *p, int off, uint32_t val);
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static int capn_set_64(struct capn_ptr *p, int off, uint64_t val);
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/* Inline functions */
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#define T(IDX) s.v[IDX] = (uint8_t) (v >> (8*IDX))
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static uint8_t capn_flip_8(uint8_t v) {
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return v;
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}
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static uint16_t capn_flip_16(uint16_t v) {
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union { uint16_t u; uint8_t v[2]; } s;
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T(0); T(1);
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return s.u;
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}
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static uint32_t capn_flip_32(uint32_t v) {
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union { uint32_t u; uint16_t v[2]; } s;
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T(0); T(1); T(2); T(3);
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return s.u;
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}
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static uint64_t capn_flip_64(uint64_t v) {
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union { uint64_t u; uint32_t v[2]; } s;
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T(0); T(1); T(2); T(3); T(4); T(5); T(6); T(7);
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return s.u;
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}
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#undef T
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static uint8_t capn_get_8(const struct capn_ptr *p, int off) {
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return (p->type == CAPN_STRUCT && off < p->datasz) ? capn_flip_8(*(uint8_t*) p->data) : 0;
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}
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static int capn_set_8(struct capn_ptr *p, int off, uint8_t val) {
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if (p->type == CAPN_STRUCT && off < p->datasz) {
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*(uint8_t*) p->data = capn_flip_8(val);
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return 0;
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} else {
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return -1;
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}
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}
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static uint16_t capn_get_16(const struct capn_ptr *p, int off) {
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return (p->type == CAPN_STRUCT && off < p->datasz) ? capn_flip_16(*(uint16_t*) p->data) : 0;
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}
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static int capn_set_16(struct capn_ptr *p, int off, uint16_t val) {
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if (p->type == CAPN_STRUCT && off < p->datasz) {
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*(uint16_t*) p->data = capn_flip_16(val);
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return 0;
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} else {
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return -1;
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}
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}
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static uint32_t capn_get_32(const struct capn_ptr *p, int off) {
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return (p->type == CAPN_STRUCT && off < p->datasz) ? capn_flip_32(*(uint32_t*) p->data) : 0;
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}
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static int capn_set_32(struct capn_ptr *p, int off, uint32_t val) {
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if (p->type == CAPN_STRUCT && off < p->datasz) {
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*(uint32_t*) p->data = capn_flip_32(val);
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return 0;
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} else {
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return -1;
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}
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}
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static uint64_t capn_get_64(const struct capn_ptr *p, int off) {
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return (p->type == CAPN_STRUCT && off < p->datasz) ? capn_flip_64(*(uint64_t*) p->data) : 0;
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}
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static int capn_set_64(struct capn_ptr *p, int off, uint64_t val) {
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if (p->type == CAPN_STRUCT && off < p->datasz) {
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*(uint64_t*) p->data = capn_flip_64(val);
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return 0;
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} else {
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return -1;
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}
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}
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static float capn_get_float(const struct capn_ptr *p, int off) {
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union { float f; uint32_t u;} u;
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u.u = capn_get_32(p, off);
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return u.f;
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}
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static int capn_set_float(struct capn_ptr *p, int off, float f) {
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union { float f; uint32_t u;} u;
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u.f = f;
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return capn_set_32(p, off, u.u);
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}
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static double capn_get_double(const struct capn_ptr *p, int off) {
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union { double f; uint64_t u;} u;
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u.u = capn_get_64(p, off);
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return u.f;
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}
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static int capn_set_double(struct capn_ptr *p, int off, double f) {
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union { double f; uint64_t u;} u;
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u.f = f;
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return capn_set_64(p, off, u.u);
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}
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#endif
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